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-   -   Weber 48 ida jettng (https://www.rx7club.com/1st-gen-general-discussion-207/weber-48-ida-jettng-1125375/)

AlexA69 04-16-18 11:06 AM

Weber 48 ida jettng
 
Whats up guys my name is alex this is my first post on the forum, I have an 83 rx7 with a bridgeported 12a from a 79 so there have been a few few problems with the car a lot of them have been small but most of those issues have been resolved, the other problems i have traced back to the carb. I just want to add im still learning a lot and the help i do get from my uncle is just general knowledge from him being a mustang guy so the thought of a rotary really messes with his head lol, but any way the carb. So the first thing is that the accelerator pedal feels very loose, like when i press down its like nothings there, then when i have te car on if i press down anymore than 25-30% the revs will drop and it will die. I just put a new muffler on it as well which i know changes things, its one that i picked up from jegs for like 60 bucks cause i live on OSU campus in ohio so there is a jegs roght down the street, there is also racing beat headers, so then when i started it up for the first time i let it run for a bit and the revs started to die and it stalled so right now on the car the set up for the carb is
40 mm venturi
f11 emusion tube
190 main jet
155 air corrector
70F10 idle jet
120 idle jet holder
2.00 mm needle and seat
basically I’m looking to eliminate that 0 pedal pressure and try to get it to run as smoothly as possible I’m still learning a lot so any help would be great thanks a lot!

aeenox 04-16-18 02:49 PM

https://cimg1.ibsrv.net/gimg/www.rx7...a01d00551a.jpg
Hey,

Do you have a spring on the throttle bracket on the carb? Usually this is where you will get your pedal feel. You will also need to have a good throttle cable/ bracket combo.

AlexA69 04-16-18 11:01 PM


Originally Posted by aeenox (Post 12268395)
https://cimg1.ibsrv.net/gimg/www.rx7...a01d00551a.jpg
Hey,

Do you have a spring on the throttle bracket on the carb? Usually this is where you will get your pedal feel. You will also need to have a good throttle cable/ bracket combo.

I have a spring and bracket but it didn’t fit on there right the spring would hit the bracket and the spring didn’t really seem to have that much tension to it but thank you!! I will check that out again I really appreciate it

aeenox 04-17-18 12:10 PM

Find a spring with more tension, the more tension the harder the gas pedal will feel. Find one that you feel is good for you. I have some friends that like a hard pedal feel so they use springs with high tension. I like it soft so I use something in the middle. Does you car stay on when you turn it on? Or does it start up and then die? Also if you get it to start can it stay on if u rev it up?

AlexA69 04-18-18 12:22 AM


Originally Posted by aeenox (Post 12268572)
Find a spring with more tension, the more tension the harder the gas pedal will feel. Find one that you feel is good for you. I have some friends that like a hard pedal feel so they use springs with high tension. I like it soft so I use something in the middle. Does you car stay on when you turn it on? Or does it start up and then die? Also if you get it to start can it stay on if u rev it up?

So I just put a new muffler on so it doesn’t stay on for long but I assumed that I would just adjust the idle and mixture screws for that. And I can rev it up but I have to do it very slowly, if I press more than 25% it will die, and if I do it to fast it will die.

t_g_farrell 04-18-18 06:59 AM

You need to read the Weber & Dellorto tuning book. Your progression circuit is not working correctly.

You can find it here: Foxed.ca - Mazda RX-7 Manuals

AlexA69 04-18-18 01:11 PM


Originally Posted by t_g_farrell (Post 12268726)
You need to read the Weber & Dellorto tuning book. Your progression circuit is not working correctly.

You can find it here: Foxed.ca - Mazda RX-7 Manuals

thank you!!

j9fd3s 04-20-18 10:54 AM

your jetting looks like it should be in the ballpark, except for the F11 emulsion tube. Weber generally does the emulsion tube by cylinder size, and the 12A wants an F7 and the 13B an F8.

with the F11 you will always be fighting a lean spot at part throttle.


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